Using a dishwasher in your home could contribute to your child's asthma, according to a recent study. The research, which took place in Sweden, found that children in families that washed dishes by hand had lower rates of asthma, eczema and allergic diseases compared to children in families that used dishwashers.
The Benefits of Dirty Hands
Allergies occur when the body mistakenly attacks harmless substances like pollen, triggering common conditions like runny noses, sneezing, skin conditions and more. It's not that the dishwashers themselves are causing allergies, researchers say. Instead, they think that exposure to a variety of microbes keeps the immune system strong and on-target, a notion known as the “hygiene hypothesis.” Because homes tend to be so clean and sanitized in developed countries, the hypothesis goes, children aren't exposed to enough microorganisms.
Washing dishes by hand, the scientists suggest, is one more way to get kids' bodies used to fighting off disease. "We therefore speculate that hand dishwashing is associated with increased microbial exposure, causing immune stimulation and, hence, less allergy," Dr. Bill Hesselmar, an associate professor of allergy at Queen Silvia Children's Hospital in Gothenburg, Sweden, said to HealthDay.
The kids in the hand-washing contingent had only half the incidence of allergies as the kids in the dishwasher families. The presumed effect was largest on asthma -- 1.7 percent of hand washers had it, compared to 7.3 percent of kids with dishwashers. It turns out that children should be grateful to their parents for their post-dinner chores after all.
The Price of Efficiency
That doesn't mean it's time to get rid of the dishwasher just yet. "I'm not convinced it's going to make that big a difference," Dr. Todd Mahr, an allergist at the Gundersen Health System in La Crosse, Wis., and a member of the American Academy of Pediatrics, said to NPR. Your dish cleaning habits are just one out of many ways that kids will or will not get exposed to microbes.
There are downsides to hand washing, too. Unfortunately, washing dishes by hand turns out to be more wasteful and expensive than using a modern dishwasher. According to the federal Energy Star program, you can save almost 5,000 gallons of water and $40 on your utility bills annually by using a dishwasher as compared to hand washing -- and that's not to mention all the extra time you lose doing the job manually. You can reduce the amount of waste in hand washing by filling a basin with water and not running the sink constantly, but it's still tough to beat a dishwasher for efficiency.
Ultimately, it's up to each family to decide on the tradeoffs. Unless more corroborating research emerges, you might consider keeping the dishwasher, and washing dishes by hand only part of the time. Or rely on the many other ways your kids can get exposure to helpful microbes, so they can build healthy immune systems — and get them to help you with other chores instead.